Interference-preventer for wireless-telegraph circuits.



BEST cw? W. L. WALKER. INTERFERENCE PREVENTER FOR WIRELESS TELEGRAPH CIRCUITS.

APPLICATION FILED JAN.27, 1910 8 Patented Oct. 29, 1912 2 SHEETS-SHEET 1 '0 PIK E11 JM ENTO'R A TTOIEIYEXJ W. L. WALKER. INIBRFERENGE PREVENTER FOR WIRELESS TELEGRAPH GIRGUITS'. APP'LIUATION FILED JAN. 27. 1910 I 1,042,855. Patented 0012529, 11912. 5 2 sums-sum 2. v7 [0/9 7 /3 7 /0. FAT/6 H'niar 6777 N 20111256" S conda C'orzdcrwe r A TTORNEJgJT sires TNT ILLI 'L. WA KER, or Bos'romMAssAcHUsn'rTs.

v mrnnrminncn-rnsvnnrnn roe WIRELESS-TELEGRAPH CIRCUITS.

Application filed may at, 1910. Serial No. 540,318.

To dliwhom it may concern."

i: Be it known that I,LW1LLIAM L. WarlKnn, a citiien of the United States, and resident gof Boston, in. the'county of Suifolkand Statenf Massachusetts, have invented new and useful Improvements in Interference-c I Preventersfor Wireless-(telegraph Circuits, ofivhieh the following a specification.

My invention relates to tuning lItSlLlli- '10 mentsfforfwlreless' telegraph receiving sta- 1t i ons','and consistsin improvements in the construction of inductance COllS and associt lted appa ratus,iwhereby the operator has at 2o ratus, the-receiving operator can readily minimize or prevent;interference from wave sources to which his resonant circuit is not attuned, and at. the same time may preserve g orle'mphasize-the'clearness and intensity of fthe' si'gnals he desires to receive. As sharp rresonaiioe obtained bya given adjustment of he circuit may result in failure to obtain desired 's'i 'e' ex*act proper adju. nt,-the includes an arrangementbywhich dull resonance may be utilized when the opi iting for signals of, which the 31's. not known.

er fd eit he mechanical adjuncts of my im )roved U I Qapparatus aliord an easy and accurate mode of tuning thestation with any known antenna within range, or a receiving I instrument-aim a suitable standard waveto lengthpand in general enables the operator to utilize existing conditions to best advantage. f i

In. the drawings hereto ,annexed which illustrate' any invention in its preferred I form -Figured is an elevation, partly in ection, (ta'ken at the dotted line marked 1 n Fig. 2) showing a mode of mounting the coils of a transformeryFig. 2. shows, on a. larger scale, t front of a part of the ap-- pa-ratugin elev t1o'n, a portion being broken ray toshoi of the. interior; Fig. 25

wstheel ctrical arrangement of. the tunupparatu diagrammatically; and

I Specification cf Letters Patent.

gnals-the. circuit being slightly r e arrangement and simplicity Patented oeaeanam.

is a horizontal. section on a smaller scale "taken through the case just above the'primary coil. 1

Referring to Figs. 1 and 2, which illustrate the mechanical arrangements and con venient grouping-0f the several parts of the tuning apparatus; A represents a casing in which is mounted an inductance coil PC, the

turns of which are wound upon a spool or cylinder A, This coil, which we may regard, and for convenience term' a primary coil, is composedof a suitable number'of inductancesections wound upon the cylin- 'der A. and connected in the manner presl ently to be described-with reference to Fig. 3. A complementary inductance coil which we may regard the secondary, is shown at- SC wound upon a spool or drum B, and this coil is also-subdivided into aseries of inductance sections, connected, arranged and controlled as will he-described with reference to Fig. '1he casing A is provided with an aperture preferably circular and concentric with the coils PC and SC and the spool B is mounted to slide axially upon a' track represented by the rod I) mounted in front upon the standard I) and at the rear upon a portion of the casing A. By means ofa feather and groove connection indicated at (i in Fig. 2, the spoolB and its inductance coil'SC may slide but not rotate upon the su 'iporting rod D. A controlling handle B, is mounted at the front of the spool 13 and carries the plate E and fingers E F, I 7

etc. of a fan switch. TheIindex finger. E of thisfan switch is electrically connected through platelfl to the rod 1) which aflords means for making connection with an outside lead. The fingers F to l! inclusive of the tan switch are mounted in an insulating sector. l .v 2

Contact pieces arranged in pairs and seatedin insulating material at. the face of the spool 13 are shown in Fig. 2 at stations 1, 2, 3, l, 5, 6, 7, 8, and 9'and these contact members, with Fig. fan switch, convenient means for determinin; and selecting the inductance the secondary coil SC.

The subdivisions of inductance sections of the primary coil PC are selectively included in circuit by means of the keys K to K" .values of' with inclusive which are shown in Fig. 2 as occup ing stations marked on the casing etters from A to J inclusive. These keys operate upon contact members generally designated in-Fig. l by L, by the action of wedge-shaped ends such as is also seen in Fig. l. One of the inductance subdivisions or sections of the primary coil PC is in contact with a sliding member G which is joined electrically to one; of the main leads of the apparatus. This sliding memher is indicated in part in Fig. 2' and 1s carried by the handle G which operates the contact member by sliding back and-forth upon the slide or track G. The track or rod D will preferably bemarked or callbrated with a scale as shown in Fig. l for convenience in determining the tion having its terminal at a, and succeeding sections at 7), 0, (Z, c, f, g, h, and so on.

illustrated in Fig. 3.

Lead wires, shown in part in Fig. 1, connect these terminals with the contact members L, in the manner diagrammatically Connections collectively designated as s (Fig. 1) establish communication between sections of the second- I ary coil SC and the contact points at stations 1, 2, 3, 4, 5, 6, 7, 8, 9,-in the manner presently to be described, and illustrated diagrammatically in Fig. 3.

Referring now to Fig. 8: The two mutually complementary inductance coils PC and SC are shown in diagram. The coil PO is subdivided into inductance sections. The first section included between points p, 72 which we will regard arbitrarily as the first section in the coil, makes contact with'the sliding contact shoe G which is carried on the track G and operated by the handle G previously referred to in connection with ig. 2. This sliding contact affords a fractional adjustment of inductance values by. connecting in at individual turns of the coil between 7) and "79 and it is through this sliding contact piece that connection 1S made to the main lead PL". The other main lead PL terminates in a plurality of contact 1 wedgeshapedoperative. ends at k to k inclusive, operateuponspring members or contact pensv Z n to Z n inclusive. The contact members which (under the control of keys K to 19 inclusive) determinethe second pair of the first group is connectedwithu terminal of the coifijnext in series to thefirst coil w ich lies between p and p. The arrangement of the other groups of contact members is identical with thatv of the first with the exception that the last group, though shown as identical in construction with the others; includes a member n which performs no electrical function but is provided merely for the sake of in building up a longer seriesof contact groups if'it should be desired, The inductance sections or subdivisions have for their respective terminals the points 39 p uniformity in construction and for facility P 2 r. 2 2' 1 7 r 1 1 and so on to p The odd numbered terminal points from p to 79 may be selectively connected through the pairs. of contact members Z n to Z n" inclusive with the main lead PL: The controlling keys K, to K are shown in Fig. 3 in the positions represented by Figs} and so that the wedge shaped ends is to is inclusive are withdrawn to allow the contact members Z mto Z m inclusive to be cut out of contact and the pairs of contact members a 0 to 42 0 to be in contact. If, now, one of the keys as K be depressed so as to swing itsiwedge shaped end 70 forward and, upward, the contact members Z n vwill be forced apart breaking the contact between a and 0 and making contact between m and Z and thus connectin the terminal point p with the main lea PL. The other main-lead PU Wlll. make connection with the coil between points p and p at any desiredturn'by means of the slidin member G thus completin the circuit om one mainlead to theot er throu h an inductance section of the coil PC. are in'elevated position as shown in Figs. 1- and 2, the disposition of thegroups of contact members is such that all of the inductance sections of the coil PC are connectedin series nd the first coil is always in electrical connection with the main lead PL. The connection with the other main lead PL isselectively determined by-the depression of one of the keys so that whateverikey is depressed the inductance sectionsbetween the first section and that controlled by the key selected will beincluded in the series between the main leads, and

iii-n en the keys K to K all inductance sections which are not so included are left completelyopen or deadended so'thatthey do not produce disturbmg resonance and are entirely eliminated to all practical intents and purposes. c In surninary-,- t he arrangement. of the prif.in ary';ceil and its sections is, as follows: Q The coil is subdivided into indepe dent sect ons, normally in series connected each other, but out of circuit with ithe-;jontside, or main, leads. Groups 'of coilsection",'connecto1's are provided, each group consisting of two pairs of contact members,

one of the first pair connectedto one of the 'main leads, the other.of that first pair .to-

gether with one of the second pair connect- I ed to a terininalor coil-section, the remain- 1ng one of the second pair connected to a terminal of thenext section, the first pair normally out of electrical contact with each other, the'second pair normally in contact.

Thefirstcoil-section is connected at one terminal with a contact member of its group, at its other terminal with a main agd, preferably by sliding or step by step contact. Thelast coil section is normally dead-ended. A controller is provided to operate with each group of-contact members, its; action, to throw. the condition outof normal, is to cause the members of the first pair of contact members to makecontact, and totbreak contact between the members of--;the second pair. This breaks the nor- .malseries'connection between the coil sectionson either side of the contact member.

betweenthemain leads, if two non-adjacent controllers are operated, then the coil sections between the first'secti'on and the first operated controller as one coil, will be in parallel with the .coil sect-ions between the first and .second operated controller, as another coil. Thus. any number of coil sections may be .put in between the main leads in, series, and pairs of sections or groups of sectionsmay be put in between the main leads in parallel. A large selection of inv ductancg values is thus made available.

so stepping tu 11 "tion, afford Coil sections not in connection are open at both ends, and thus-introduce no disturbing resonances. The sliding main lead contact,

by turn on the first coil secfine adjustment. Though its leave a portion of the first operation may I .coil section only partially "dead-ended, the

dist-urb'ng resonanceof this loose end is not to be reckoned with; its period will be so far'out of harmonic range of the active coil sections.

The secondary coil SC like the primary is subdivided into' inductance sections of which the first has one terminal a in connect-ion with the main lead SL Normally the terminal points from s to 8 inclusive of these inductance sections. are open or dead ended by .the fanswitch arrangement indicated in Fig. 2; theseinductance sections of the secondary soil may be included cumulatively or by addition and subtraction,

between the main Ieads SL and SL. The

contact points at the stations 1, 2, 3, 4, 5, 6, 7, 8 a1id'9 are with one exception arranged in pairs, the terminal point 8 of the first.

inductance section is connected to the first contact point of the pair at station 1, the other member of.this pair being connected to the terminal point a of the next adjacent inductance section. The other terminal point 8 of this section is connected to the first member of the pair at station 2 and terminal point a of the next inductance section-in series to the second of the contact. points at station 2, and so on to station 9 where the single contact'point is connected with the'fterminal point 8 of the last inductance section'in the series. The main lead SL is connected to the switch plate E (see Fig. 2) through the rodD andas here-1 tofore stated the index finger E 'of the fan switch is in electrical contact with the switch plate. It, now, the handle B be turned to the right or clockwise as viewed" in Fig. 2 and the index. finger E placed-fin contact with the first of the pair at station 1, so I that the pointerof the finger 'E' 'i is overthe numeral 1 marked on the head of the spool B, the first inductance section between points sf and s will :be' included in circuit between the main leads SLSL. If theindex finger E" be then movedto' the station marked 2 I the first and second indugtance sections will then be includedin cii' series andso' on until the indeifinger-Ef stands at thestation marked 9 when, all of the' sections of coil SC will be inserig ihotween the main leads. 1 I g g The inductance values oi the icircuit'm" which the 'cOilsjPO-SGP frformtheir tune-- by'means of the-control keys of the primary and the control switch oftjhe secondary, but

tion may not only be ac acted: and adjusted may' also be varied bygn'i ingthesecondary;

coil along the rod B,

It will now be observed that the hiechani-E cal and structural arrangement oftheabove' described inductances and adjusting-Jami se-E lecting devices enables the operator to con .trol and select his ind'uctances readily and accurately. The handle B not only controls the movement of the fan switch'but is also a convenient handle by wh1ch,.to slide the secondary coilQSC bodily to any desired position uponits track and these operating devices of the apparatus are conveniently close to the controlling keys by which the inductance values of the primary are selected, and the sliding contact controlled by the handle G is also easily accessible and near to the other controlling handles and keys of this portion of the apparatus. All of the controlling devices are permanently in place so that the inconvenience, uncertainty and fumbling which attend the use of loose and separate contact plugs is avoid-- ed. After an operator has become accustomed to this apparatus he can select and operate the keys of the primary merely by senseof touch leaving his eye free to observe the positions of such other adjusting arrangements as he may wish to manipulate at the same time such as, for instance, the pointers which indicate the capacity values of condensers. Again, in tabulating inductance adjustments suited to communicate with stations of whichv the period is known, the devices above described will be found convenient in that they involve a minimum number, of tabulation factors. If it is found for instance that perfect tuning for a given station is secured with key K at station D. depressed, index finger E at station 2 and the handle B at the scale mark 35 on the rod D, the tabulation for this station will simply be D-2-35 so that after a short term of actual operation the arrangement of tabulation factors can easily be remembered, each group of three representing as by a cipher code a given station with which the operator is accustomed to communicate. Normally the sliding point (Fig. 3) will be so placed that the total number of turns of the first inductance section will be in circuit and after 'the tuning is perfected as far as may be by operation of the other mechanical adjuncts on the apparatus, finer adjustments may be made if necessary by means of the sliding contact G. Ordinarily, only one of the keys K to K inclusive should be depressed at a time and it is only in extraordinary cases that the operator may wish to decrease the inductance by including sections in paral' lel, depressing more than one key. The inductance values of the several sections in each of the coils may be equal but preferably should progrcss say by having the lowest value of inductance in the primary controlled by the first key K at station A and having the values represented by the keys increase to the right. When'a key controlling the required inductance is down only the portion ofthe coil required is in circuit, the, remainder being out of circuit at both ends eliminating the disadvantages of disturbing resonance incident to the e'mployment of inductances which are inca- In Fig. 3,.the main .1,042',e'es I pable of being wholly cut out. Changes in nductance yhlues can be made instantly.

3 leads are shownas connected withuan apparatusof standard on rangement which 1s merely shown diagrammatically. Detectors which may be of crystal rectifier type are indicated at H and control switch at J", J and J. The arrange ment and operation of such an apparatus and its relation withthe inductance coils PC SC will be understood by those skilled in the art without detailed description.

\Vhat I claim and-desire to secure by Let ters Patent is:

1. In a transformer fbr resonant cincuits, an inductance coil comprising a-series of inductance sections, a main lead connected with the first of said sections, groups of contact members, corresponding in number to the inductance sections, each'group comprising two pairs of contacts, the first pair of each group normally out of contact, one of said first pair connected with a main lead, the other to a terminal of an inductance s80 tionfthe second pair of each group normally in contact, one of said second pair connected to the inductance section terminal to which a member of the; first pair is con nected, the ether of said second pair connected with a terminal of the inductance section next in series, and means to reverse the connection relations between the pairs of contact members in any group, so as to connect the pair which is normally out of contact, and separate the pair which is nor 100 mally in contact.

- 2. In a transformer for resonant-circuits, an inductance coil comprising a series of inductance sections, lead connected by a main sliding turn-to-turn contact with" the first of said sections, groups of contact members, corresponding in number to the inductance sections, each group comprising two pairs of contacts, the first pair of each group normally out of contact, one of said first pair connected with a plain lead, the other to a terminal of an inductance section, the second pair of each group normally in contact, one of said second pair connected to the inductance section terminal to which a member of the first pair is connected, the other of said second pair connected with a terminal of the. inductance section next in series, and means to reversev the connection relations between the pairsof contact members in any group, so as to connect the pair which is normally out of contact and separate the pair which is normally in contact.

3. 'ln ntransformer for resonant circuits, an inductance coil comprising a series of inducta-nce sections, a main lead connected with the first of said sections, groups'of contact members, corresponding in numbento the inductance sections, each group compristhefirst pair of ing two pairs of contacts,

eachgroup normally out of contact, one of i .said first pair connected with a main' lead (the other to a terminal of an inductance sec-' tion, the second pair of each group normally in contact, one of said second pair connected to the inductance section terminal to which a member of the first verse the connection relations between the pairs of contact membersinany group, so"

i tact'po ints of eaghpair, a contact point con-.

pair is connected, the other of said second pair connected with a terminal of the inductance section next in series, means to reas to connect the pair which is normally out of contact, and separate the pair which is normally in contact, in combination with a complementary inductance coil which comprises a serlesof inductance sections, whereof" the first is connected at one end to a v main lead, a series of pairs of-insulatedcon- 1;: 2o"

tactp'oints, terminals of adjacent inductance sections connectedrespectively with the conlnected with' the final terminal of the last ""finductance section in the series, a second main lead and means to connect'the inductance sections, through the contact points i 3 .by' serial addition or subtraction.

4, 'In a transformer for resonant circuits,

an inductance coil comprising a series of inductance sections a main lead connected-by a sliding turn-tp-turn contact-with the first of said sections, group; of contact members,

corresponding innumoer-to the inductance sections, each group comprising two pairs of contacts, the first pair of each group normallyout of contact, one of said first pair connected'with a main lead, the other to a terminal of an inductance section, the second pair of each group normally in contact, one of said second pair connected to the inductance section terminal to which a member of the first pair is connected, the other of said second pair connected with a terminal of the inductance sectlon nextiin series, means to reverse the connection relations between the pairs of contact members in any group, so as to connect the pair which is normally out of contact and separate the "contact points traction,

tact point connectedwith the final termi-,

nal of. the last inductance section in the series, a second mainlead, and means to connect the inductancesections, through the by' ser al addition'or sub "5. In a transformer for resonant circuits,

tan inductance coil'comprising a series of inducta'nce sections, a main lead connectedwith cent inductance sections connected res the first oi said sections, groups of contact members, correspondin in number to the inductance section's, eac group comprisin two pairs of contacts, the first pair of eac group normally out of contact, one of said first pair connected with a main lead the other to a terminal of an inductance section, the second pair of each group normally in contact, one of said second pair connected to the inductance section terminal to whichfa' member of thefirst pair is connected, the other of said second pair connected 'wlth ,aterminal of the inductance sect-ion:next"in series, means to reverse the connection'ii'ela tions between the pairs of contact members in any group, so as to connect the pair which is normally out of contact, and separate. the. pair which is normall in contact, in com ination with a comp ementary inductance coil which comprises-a series of inductance sections, whereof the first is connected at one end to a main lead, a series of pairs of insulated contact points, terminals ofiadja tively with the contact points of each pa lwith' the final terx minal o the lastinductance section in the; serles, a second mam lead, and means to connect the inductance sections, through the" contact points by serial addition or subtrac-' tion, the mutuallyv com lementary inductanee coils bein relative y axially movable.- 6. In a trans ormer for'resonant circuits, an inductance coil comprising a series of inductance sections, a main lead connected by sliding turn-to-turn contact with. the first'of said sections, groups of contact -members, corresponding in number tothe inductance sectionsg" each group comprising two pairsof contacts, the first pair of each group noranally out of contact, one of said first pair connected with a main lead, the other to a terminal of an inductance section, the sec- 0nd pair of each group normally in contact,

one of said second pair connected tothe in ductance section terminal to which a member of the first pair is connected, the other of said second air connected with a terminal of the in uctance section next in series, means to reverse the connection relations between the pairs of contact members in any group, so as to connect the pair which is normally out of contactand separate the pair which is normally in contact, in c om- 'bination with a complementary inductance coil which comprises a series of inductance sections, whereof the first is connected at one end to a main lead, a series of pairs of insulated contact points terminals of adjacont' inductance sections connected respec tively' wit-hjthe contact points of each pair,

series, a second main lead andmeans to connect the inductance sect1ons,through the acontact, point connected"with"fina l ter- I minal of the last i-nductancesection 1n the contact by serialv addition or subtrac;

tiomgthe mutually complementary inductancefuoils being relatively axially movable.

7., In a tunin vdevice for resonant circuits, a casinggan in uctance coil mounted in the casing, 'a complementary inductance coil movable and adjustable in axial direction, each coil subdivided into a series of inductance sections, means accessible on the exterior of the casing, to include one or more sections of the stationary coil in circuit, and to isolate the remaining sections, and means carried by the movable coil, to include one or more sect-ions of said coils in circuit and to isolate the remaining sections.

8. In a tuning device for resonant circuits, a casing, an inductan'ce coil mounted in the casing, a complementary inductance coil movable and adjustable in axial direction, each coil subdivided into a series of inductance sections, means accessible on the exterior of the casing, to include one or more sections of the stationary coil in circuit and to isolate the remaining sections, and means carried by the movable'ooil, to include one or more sections of said coil in circuit and to isolate the remaining sections, one lead con nection of the stationary coil having sliding turn-to-turn contact with a section of said coil.

' 9. In a tuning device for resonant circuits, a casing, an inductance coil in the casing,

,3 J c the casing provided with an opening concentricwith said coil, a complementary inductance coil mounted to move in and out 0t said opening and adjustable axially on a track, said track, each of said coils subdivided into inductance sections, means accessible on the exterior of the casing, to include one or more sections of the stationary inductance coil in circuit, and means carried by the movable coil, including a switch and handle therefor, to include one or more sections of said coil in circuit and to adjust the positionpf said coil on its track.

- '10. In a tuning dev":e for resonant circuits, a casing, an inductance coil in the casing, the casing provided with an opening concentric with said cdil, a complementary inductance coil, mount/ed to move in and out of said opening, and adjustable axially on a track, said track, each of said coils subdivided into inductance sections, means acces sible on the exterior of the casing, to includelone or more sections of the stationary inductance coil in circuit, and means carried by the movable coil, including a switch and handle therefor, to include any one or more sections of said coil in circuit and to adjust the position of said coil on its track, one lead connection of the stationary coil having sliding turn--toturn contact with a section of said coil.

Signed by me at Boston, Suffolk county, Massachusetts this eleventh day of January WILLIAM L. WALKER. Witnesses:

Oman ROBERTS, CHARLES D. WOODBERRY. 

